title: Treatment with potassium bicarbonate lowers calcium excretion and bone resorption in older men and women.
abstract: BACKGROUND
  Bicarbonate has been implicated in bone health in older subjects on acid-producing diets in short-term studies.
  
  
  OBJECTIVE
  The objective of this study was to determine the effects of potassium bicarbonate and its components on changes in bone resorption and calcium excretion over 3 months in older men and women.
  
  
  METHODS
  In this double-blind, controlled trial, 171 men and women age 50 and older were randomized to receive placebo or 67.5 mmol/d of potassium bicarbonate, sodium bicarbonate, or potassium chloride for 3 months. All subjects received calcium (600 mg of calcium as triphosphate) and 525 IU of vitamin D(3) daily.
  
  
  METHODS
  Twenty-four-hour urinary N-telopeptide and calcium were measured at entry and after 3 months. Changes in these measures were compared across treatment groups in the 162 participants included in the analyses.
  
  
  RESULTS
  Bicarbonate affected the study outcomes, whereas potassium did not; the two bicarbonate groups and the two no bicarbonate groups were therefore combined. Subjects taking bicarbonate had significant reductions in urinary N-telopeptide and calcium excretion, when compared with subjects taking no bicarbonate (both before and after adjustment for baseline laboratory value, sex, and changes in urinary sodium and potassium; P = 0.001 for both, adjusted). Potassium supplementation did not significantly affect N-telopeptide or calcium excretion.
  
  
  CONCLUSIONS
  Bicarbonate, but not potassium, had a favorable effect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults.
authors.affiliation: Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA. Bess.Dawson-Hughes@Tufts.edu
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
authors.forename: Susan S
authors.initials: SS
authors.lastname: Harris
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Palermo
authors.forename: Carmen
authors.initials: C
authors.lastname: Castaneda-Sceppa
authors.forename: Helen M
authors.initials: HM
authors.lastname: Rasmussen
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Dallal
mesh_terms: D000368:Aged; D001639:Bicarbonates / Q000008:administration & dosage*; D001862:Bone Resorption / Q000517:prevention & control*; D002118:Calcium / Q000652:urine*; D024042:Collagen Type I / Q000652:urine; D003404:Creatinine / Q000652:urine; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000652:urine; D011188:Potassium / Q000097:blood; D017680:Potassium Compounds / Q000008:administration & dosage*
chemical_list: D001639:Bicarbonates; D024042:Collagen Type I; D010455:Peptides; D017680:Potassium Compounds; C052929:collagen type I trimeric cross-linked peptide; D003404:Creatinine; C026329:potassium bicarbonate; D011188:Potassium; D002118:Calcium